Speaker
Description
Methane clathrates are solid materials ocurring in the depths of oceans. Their structure composes of water cage-like framework which surrounds methane molecules. One of the basic properties which decides the stability of the structure is the strength of the binding between methane molecules and the water framework. Interestingly, this property is very difficult to calculate accurately using modelling methods based on quantum mechanics [1,2]. We have used two clathrate models to understand the origin of the difficulties and to assess the quality of promising quantum mechanical methods. The first structure is a single cage formed by twenty molecules and a single methane molecule [1], second is a solid clathrate [2]. I will discuss some of the interesting observations that we made while studying these systems. For example, decomposing the binding energy of the single cage into contributions of dimers and trimers of molecules clearly showed that the reference binding energy is not very precise and we were able to improve it. Moreover, I will discuss the transferability of the observations made for the cluster to the bulk clathrate.
[1] M. J. Deible, O. Tuguldur, K. D. Jordan: J. Phys. Chem. B 118, 8257 (2014)
[2] S. J. Cox, M. D. Towler, D. Alfe, A. Michaelides: J. Chem. Phys. 140, 174703 (2014)
